In a manufacturing process of an electronic component, processing residues or surface contaminants adhering to a substrate are removed by a wet cleaning process. In the wet cleaning process, a water-based cleaning solution is supplied to a surface of a substrate, rinsing with pure water is performed, and thereafter the surface of the substrate is dried. A pattern formed on the substrate has become finer in recent years, and there are problems such that the pattern is collapsed by a surface tension of a liquid when the substrate is dried after the wet cleaning process.
A known drying method for preventing collapse of a pattern is a drying method that uses sublimation of a sublimation material to dry a surface of a substrate (hereinafter, also “sublimation drying”). In the sublimation drying, a solution containing a sublimation material is spin-coated onto a surface of a substrate, and a solvent is removed from the spin-coated solution to precipitate the sublimation material. The precipitated sublimation material is changed from a solid phase to a gas phase (sublimation), so that the sublimation material is removed from the surface of the substrate.
The sublimation drying uses a solution in which a low molecular organic material is dissolved in a highly volatile solvent, as a sublimation material containing liquid. However, the sublimation material containing liquid has a low viscosity that is 50 cP or less, and its solute is a low molecular material unlike a resist material and a SOG (Spin on Glass) material. Therefore, there is a problem of film formability. Due to this, unevenness in micron order in film formation is generated in the conventional sublimation drying, and this unevenness in film formation may cause collapse or deformation of the pattern on the surface of the substrate.